Drill-bit agitator



Feb. 4, 1930. J. BISHOP 1,745,351

DRILL BIT AGITATOR Filed Oct. l, 1928 hex'fo JoHN EMSHOP.

'Vj/@Mm Patented Feb. 4, 193() UNITED As'm'rEs PAT-ENT OFFICE f JOHN BISHOP, OF LONG BEACH, CALIFORNIA, ASSIGNOR, BY DIRECT AND MESNE AS- SIGNMENTS, OF ONE-HALF TO GEORGE G. OSBORN, OF LONG BEACH, CALIFORNIAl AND ONE-HALF TO THEODORE ALBERT PONTING, OF NEWPORT BEACH, CALIFORNIA by a shock is imparted toa drilling bit dur-l ing the drilling operation so that the bit'will more effectively penetrate a hard or rock formation.

An object of my invention is to provide `an agitator whichY is operated bythe rotation of the drill pipe during the drillinglop.- eration and whichwill strike a series of blows upon the bit at each revolution thereof. Y v

A further object is to provide an agitator which is automatically set when the bit s run into the hole and is therefore Aavailable at all times and at any depth in the hole.

Other objects, advantages, and features of invention may appear from the accompanying` drawing, the subjoined detailed description, and the appended claims.-

Figure 1 is a side elevation, partly in section, of my agitator.

Figure 2 is a side elevation of the same.

Figure 3 is a 'sectional view, taken on line 3, 3, of Figure 1. Y l

Figure 4 is an enlarged fragmentary side elevation of the stationary ring and holding dog therefor.

Referring more. particularly to the draw# ing, the ynumeral v1 indicates a mandrel, the.

lower end of` which is enlarged to form a head 2. The bit 3 of any' desirable type screws into the head 2 in'the usual and wellknown manner. A threaded pin 4 is provided on the upper end of the' mandrel 1 and the drill pipe, or the like, (not shown) is screwed thereon. A ring 5 fits upon the mandrel 1 and rests against the top of the head 2. `This rihg is heldQstationary when the tool is in the hole and the mandrel rotates therein.

- The ring 5 is held stationary when in the hole by meansof a .pluralityof dogs 6. These dogs are pivotally mounted in the ring 5 on a pin 7 and are normally urged outwardly into engagement with the wall of the hole by a. spring 8. This spring bears againstlthe wall of arecess '9 in which the dog fits and extends into a bore 10 in the dog. The outer i v`'surface of the dogs are curved so that iwhen the tool is pulled upwardlyin the casing the dogs engaging said casing will be urged i 4Appliration led October 1,

. f .y DRILL-Bfr AGITATQR 1928. Serial 110,309,434.

vof the' ring 5 and strikes thereon, as Willbe further described.

)n the top of the ring 5 I provide a plurality of vcam surfaces 14, which cams terminate in an abrupt drop 15 to cause the striking action. The collar 12 is provided with similar co-aeting cam surfaces 16 which coact with the surfaces 14 to raise the collar during the rotation of the tool. l That is, the mandrel 1 rotates with the drill pipe and the ring 5 is -held stationary,'and thus the collar 12 will be moved over the cam surfaces 14 to alternately and abruptly drop the collar upon the top of the ring 5.

A coil spring 17 surroundsthe mandrel l and bears against the top of the collar 12. A nut 18 screws onto the upper end of the mandrel 1 and against the top of the spring y17. Thus the tension of the spring against the collar 12 can be regulated. The spring 17 acts to forcibly move the collar 12 downwardly against the ring 5 and this shock is imparted through the head 2 and Athence to the bit 3, thus assisting the bit in forcing its way through a hard or rock formation. c

Having described my invention, I claim: i

1. An agitator for a drilling bit compris-v ing a mandrel, a bit secured to the lower end of the mandrel, said mandrel being adapted -to be secured to the drilling pipe, and means on the mandrel adaptedto strikeupon the bit during rotation of the mandrel, said means comprising a ring journaled on the mandrel, means engageable with the wall of the bore whereby said ring is held stationary,

2. An agitator-for drilling bits comprising a mandrel, a bit secured to the lower 'end of the mandrel, a ring on the mandrel, dogs on the ring adapted to engage the Wall of the bore whereby the ring'is held stationary, a

e collar on the mandrel, means slidably keying said collar to the mandrel, spring means engaging said collar whereby it is forcibly urged against the ring, and co-actng means on the collar and ring whereby said collar is alternately raised and dropped upon the ring to impart a shock to the bit.

3. An agitator for drilling bits comprising a mandrel, a bit secured to the lower end of the mandrel, a ring on the mandrel, dogs on the ring adapted to engage the wall of the bore whereby the ring is held stationary, a collar on the mandrel, means slidably keying said collar to the mandrel, spring means engaging said collar whereby it is forcibly urged against the ring, and co-acting means Y,

on the collar and ring whereby said collar is alternately raised and dropped upon the ring to impart a shock to the bit, said last named means comprising a plurality of inclined cam surfaces on the upper facing of the ring, said cam surfaces terminating in an abrupt drop, said collar having co-acting surfaces co-operating with the lirst named cam surfaces whereby the collar is alternately raised and dropped upon the ring.

4. An agitator for drilling bits comprising a mandrel, a bit secured to the lower end of the mandrel, a ring mounted on the mandrel, a plurality of dogs pivotally mounted on the ring, spring means urging said dogs outwardly into engagement with the wall of the bore whereby said ring is held stationary, a striker collar slidably keyed to the mandrel, a plurality of cam surfaces on the upper face of the ring, a plurality of co-operating cam surfaces on the lower face of the collar, a spring encircling the mandrel and bearing against the top of the collar, and a nut screwed onto the mandrel against said spring.

In testimony whereof, I aix my signature.

JOHN BISHOP. 

